Diabetics must monitor their blood sugar levels directly to ensure that these levels remain within an acceptable range. When blood sugar levels drop below a first threshold, the diabetic suffers from a physical condition known as hypoglycemia and, when blood sugar levels rise above a second threshold, the diabetic suffers from a physical condition known as hyperglycemia.
Although mild hypoglycemia and hyperglycemia are common among diabetics, and generally regarded as manageable, moderate or extreme hypoglycemia and hyperglycemia can be life-threatening. When in either condition, the diabetic is often unable to think clearly, and may therefore be unaware that a dangerous condition exists. Failure to take prompt corrective action, such as consuming sugar when the diabetic is hypoglycemic or receiving an insulin injection when the diabetic is hyperglycemic, can result in serious medical complications. As either condition worsens, the diabetic can enter into a diabetic coma, which may result in death.
To avoid either condition, the diabetic must maintain his or her blood sugar level within an acceptable range. This is preferentially done by frequent, regular monitoring of his or her blood sugar level. This is typically done by pricking the finger in order to obtain a sample of blood, placing the blood on a disposable test strip, and then relying on a machine to perform chemical or optical analyses of the blood to determine the sugar level. Many diabetics find this procedure to be bothersome, if not painful, and are not diligent about checking blood sugar levels. Even more problematical, the test strips, which are typically not reusable, are commonly quite expensive. Because of the inconvenience, discomfort and cost, many diabetics do not test their blood appropriately, and therefore fail to discover the presence of hypoglycemia or hyperglycemia. Among diabetics who do not monitor their blood sugar levels diligently, the progression of mild conditions to conditions requiring medical attention is an all-too-frequent occurrence.
There is a need for a noninvasive, unobtrusive technique to detect the possible onset of hypo- or hyperglycemia.